150mi/5hr =30 mi/hr so the answer is 30 mi/hr
Answer:
Light is moving at the speed = 77.78 km/min
Step-by-step explanation:
Given:
Distance between island and point P = 5 km
Moving along the the shoreline when it is 1 km from P.
So, x = 1
From the above statement light makes seven revolutions per minute.
Therefore,
Solution:
From the given figure.

Substitute x = 1
-------------------(1)
Now, first we differentiate both side with respect to t.

Using chain rule.



Substitute
from equation 1.


Substitute 

Applying cross multiplication rule.


Therefore, light is moving along the shore at the speed of 77.78 km/min
It would be 89.60000000000
I believe the answer is A
Answer:
CD=9
Step-by-step explanation:
ΔABD=>
AD²=AB² + BD² [Pythagorean Theorem]
BD²= AD²-AB²
BD²=9²-3²
BD²=72
BD=√72=6√2....(1)
ΔBCD=>
CD²=BD²+BC²
CD²=(6√2)² + 3²
CD²=72+9
CD²=81
CD=√81
CD=9